jQuery $(document).ready() failing in IE6

问题:

I have the following code:

// Creates a timer to check for elements popping into the dom            
timer = setInterval(function ()
{          
    for (p in pixelTypes)
    {                             
        checkElems(pixelTypes[p]);
    }                            
}, 10);

// Add Document finished callback.
$(document).ready(function ()
{         
    // Document is loaded, so stop trying to find new pixels
    clearInterval(timer); 
});       

In Firefox, it works great, but in IE6, I get a "Object Expected" error on the $(document).ready line.

I can't figure out what would cause IE6 to not recognize it, jquery is fully loaded by this point.

Is this a known issue?

回答1:

Just a few pointers for anyone that's interested:

$(document).ready(function() {...}); and $(function() {...}); means exactly the same thing. The latter is a shorthand for the former.

If you develop for a large site, using multiple Javascript libraries, or you develop plugins meant to be compatible with other peoples work, you can not trust the dollar sign ($) to be associated with the jQuery object. Use the following notation to be on the safe side:

(function($) { [your code here] })(jQuery);

This passes jQuery into a self-executing function, and associates $ with the jQuery object inside this function. Then it does not matter what the $ represents outside of your function.

To get back to your question, have you checked whether the timer variable is assigned when you get the error? I believe the browser will see the $(document).ready(function() {...}); all as one line, so if you have some kind of debugger that tells you that's the offending line, it might be the timer variable...

Last thing: In Javascript, it is not correct to place open curly braces on a new line. This can cause really bad errors due to Javascripts semicolon-insertion. For further info, read Douglas Crockford's Javascript: The good parts:

http://www.amazon.com/JavaScript-Good-Parts-Douglas-Crockford/dp/0596517742/ref=sr_1_1?ie=UTF8&s=books&qid=1267108736&sr=1-1

Anyway, really hope I didn't upset anyone. Hope you solve the problem!

EDIT: I'm not sure if this is what robertz meant by fully qualified, but as far as I know, when a URL is fully qualified it means no parts are missing, ie. it's an absolute URL starting with http:// or https:// (or some other protocol). Please correct me if I'm wrong!

回答2:

I've had this same issue in the past too. It was a sporadic issue and was horrible to and reproduce.

The solution that I found was to replace $(document).ready(function() {...}); with jQuery(function() {...}) and it worked like a charm!

Moving $(document).ready(function() {...}); to the bottom didn't work for my use case.

The comments in this post are incredibly helpful (Where I first read about doing it this way)

回答3:

If anyone have the same problem you should see if when you call your javascripts you have type="application/javascript", I eliminate it and it was corrected, I think it's some problem with IE and the type Thing

回答4:

Are you sure that jQuery is loaded? Try debugging with alerts like:

alert(typeof $);

You could also try a different syntax:

$(function() {
     clearInterval(timer); 
});

---

Ok, so from your comment, the above doesn't help. The "object expected" error seems to occur with a syntax error in my experience. Is that the exact code you've got? If not, could you post it?

回答5:

Make sure your script type is text/javascript

<script type='text/javascript'

回答6:

The DateTime picker worked just fine on my local XP test, but it failed "Object Expected" once deployed on the server. After 2 days of being persistent, this is how I solved my problem, adding the Url.Content around the path of the Javascript!

<script src="<%= Url.Content("~/Scripts/jquery-1.4.1.min.js") %>" type="text/javascript"></script>

<script src="<%= Url.Content("~/Scripts/ui/minified/jquery.ui.core.min.js") %>" type="text/javascript"></script>  
<script src="<%= Url.Content("~/Scripts/ui/minified/jquery.ui.datepicker.min.js") %>" type="text/javascript"></script>

回答7:

I don't think that you should really be polling for elements the way you are.

The document ready event calls as soon as the browser has loaded enough for you to be able to manipulate the page, so you should just do your DOM processing in the $(document).ready() block.

回答8:

You could try the old skool way of checking whether the document is "ready"... Place the script just before the closing </body> tag - I believe it has the same effect as jQuery's 'ready' event - actually, it's probably quicker doing it this way.

---

In my experience the "Object expected" error in IE6 shows up because of a syntax error - it's worth putting the script though JSlint, if you haven't already...

回答9:

I ran into this problem on my machine, as was able to find a quick fix. Here's what I did:

1.Debugged my javascript with nickf's suggestion "alert(typeof $)" and got the "undefined" alert message

2.I then fully qualified my jQuery script resources.

3.Reload my page and received the "function" alert message

BTW, I am using IIS 5.1 on XP. My website is configured to use "Wildcard mapping" to take advatage of the asp.net mvc framework. I think that this configuration caused the broken links.

For more information on how to setup MVC on old versions of IIS, check out Phil Haack's post: http://haacked.com/archive/2008/11/26/asp.net-mvc-on-iis-6-walkthrough.aspx

回答10:

$(document).ready() tells you when the dom is ready, but not all assets are necessarily done coming in.

If you want to make sure all the assets are actually done loading, use $(window).load() instead. The most common use for this is to make sure that images are done loading, but it may work for your script problem as well.

回答11:

If it is in a script element which is within your body element, (i.e.) ..

The cause can be the attributes you pass with the script-tag. If it is:

<script type="text/javascript">...</script>

IE6 can give an error. You should use

<script language="javascript">...</script> 

Then the error goes away.

回答12:

I had the same issue, script error informing me that the object was undefined. I tried all the suggestions listed here with no avail. Only thing I did not consider was security, I had forgotten all about my forms authentication and turns out I forgotten about the authorisation on the scripts folder which was denying access to the jQuery libraries!!!

Hope this helps.